Cardiff Crohn's disease jubilee: the incidence over 50 years.

The incidence of Crohn's disease in Cardiff between 1931 and 1985 has been examined using hospital diagnostic indices supplemented in recent years by records from clinicians, and the departments of pathology and radiology. Four hundred and seven new patients were confirmed after all notes had been reviewed. There has been a large increase from 0.18 cases/10(5) of the population per year in the 1930s to current values of 8.3/10(5)/year. The incidence continues to rise and shows an increasing proportion of patients with colorectal disease. Peak age specific incidences occur in the third and eighth decades of life.